1. Field of the Invention
The present invention relates to an LSI defective automatic analysis system and an analyzing method therefor, and a recording medium of storing a program for causing a computer to execute the analyzing method. More specifically, the present invention relates to an LSI defective automatic analysis system configured to automatically search for a defective cause place in an LSI by use of an electron beam, and an analyzing method therefor, and a recording medium of storing a program for causing a computer to execute the analyzing method.
2. Description of Related Art
As one effective means for searching for a defective cause place in an LSI, an electron beam tester has been used. A test signal is applied to an defective LSI in a vacuum chamber by means of an LSI tester, and an electron beam is also irradiated on a surface of the LSI, so that the amount of secondary electrons created as the result of the irradiation of the electron beam is measured. A relative potential can be known on the basis of whether the amount of secondary electrons is large (the potential is relatively low) or small (the potential is relatively high). Furthermore, a system for automatically carrying out a defective cause place search on the basis of this method, has been proposed (Japanese Patent Application Pre-examination Publication No. JP-A-63-124438 (an English abstract of JP-A-63-124438 is available and the content of the English abstract is incorporated by reference in its entirety into this application) and Japanese Patent Application No. Heisei 08-149641 (which was published as Japanese Patent Application Pre-examination Publication JP-A-09-329649; an English abstract of JP-A-09-329649 is available and the content of the English abstract is also incorporated by reference in its entirety into this application).
Particularly, the system proposed by Japanese Patent Application No. Heisei 08-149641 is so constructed that, within a vacuum chamber of an electron beam tester, one of non-defective and defective LSI samples is quickly located on a measuring position by means of an LSI changing and locating mechanism, and a potential measurement is carried out for the located sample, so that a defective cause place is searched for on the basis of the measured potentials of the non-defective and defective samples. Since information of operating potentials in a normal condition, required to search for the defective cause place, is obtained from actual operating potentials of the non-defective samples, it is possible to search for the defective cause place, without information of circuit connection of the LSI to be analyzed, and without information of logical desired values when a test signal is applied, which information was required in the other system. In many cases it is actually difficult to obtain this information. Since this system can be utilized in the many cases, this system has a wide range of application.
The above mentioned system has such a problem that a considerable execution time is required because it is necessary to carry out the potential measurement at many places for non-defective and defective samples in order to search for a defective cause place.